Krzysztof Gogolewski authored Aug 31, 2022 and Marge Bot committed Sep 01, 2022

- Remove mkHeteroCoercionType, sdocImpredicativeTypes, isStateType (unused),
  isCoVar_maybe (duplicated by getCoVar_maybe)
- Replace a few occurrences of voidPrimId with (# #).
  void# is a deprecated synonym for the unboxed tuple.
- Use showSDoc in :show linker.
  This makes it consistent with the other :show commands